1. Developments of High CW RF Power Solid State Amplifiers at SOLEIL
R. Lopes P. Marchand F. Ribero T. Ruan
CWRF2012 BNL
07-11 May 2012

2. SOLEIL Amplifier

3. Summary
At SOLEIL, SSA are providing the required 352 MHz CW power: 1 X 35 kW into the Booster (BO) cavity and 4 X 180 kW into the 4 superconducting cavities of the Storage Ring (SR). Based on a design fully developed in house, they consist in a combination of a large number of 320 W elementary modules (147 in the BO and 4 X 724 in the SR) with MOSFET, integrated circulators and individual power supplies (DC/DC converter).
After 6 years of operation, this innovative design has proved itself and demonstrated that it is an attractive alternative to the vacuum tube amplifiers, featuring an outstanding reliability and a MTBF > 1 year.
Advantages of SOLEIL SSA: low noise, good linearity, high reliability, long life time, easy maintenance, simple spare parts, no HV, no X ray.

4. New developments
In the meantime, thanks to the acquired expertise and the arrival of the 6th generation LDMOS, SOLEIL has carried out developments which led to doubling the power of the elementary module (650 W) while improving the performance in terms of gain, linearity, efficiency and thermal stress.
3 years ago, 352 MHz 150 kW CW SSA with 6th generation MOSFET has been developed for the ESRF upgrade project.
Now 500 MHz amplifier based on this technology are being built for ThomX (50 kW) and SESAME (140 kW) projects. All key parts have been validated.

5. 352 MHz SSA of SOLEIL Design
Transistor
type
Power supply per module
Module Parameters
at nominal conditions
Amplifier design
& nominal power
VSWR limitation *
Comments
SOLEIL
Booster
D1029UK05 
SEMELAB
1 x 600 W 280/28 Vdc
P1dB = 330 W, G = 11 dB
 = 60 % , Tmax = 130°C
1 tower of 8 dis
Pnom = 35 kW modulated
No limit with SOLEIL Booster duty cycle
1 trip over 7 years due to a human mistake
SOLEIL SR (actual)
LR301
Polyfet
P1dB = 315 W, G = 13 dB
 = 62 % , Tmax = 130°C
4 towers of 10 dis
Pnom = 180 kW cw
70 kW full reflection
Pr = kW
MTBF > 1 year
SOLEIL SR (upgrade)
BLF574XR
NXP
1 x 600 W ♯
280/48 Vdc
P1dB = 350 W, G = 22 dB
 = 69 % , Tmax = 90°C
Pnom = 200 kW cw
Pr = kW
Much more robust
than LR301
ESRF Booster
(800W load)
BLF578
2 x 600 W
P1dB = 650 W, G = 20 dB
 = 71 % , Tmax << 75°C
2 towers of 8 dis
Pnom =150 kW modulated
No limit with ESRF Booter duty cycle
In CW Pr limited at 5 kW
for Pi = 150 kW
ESRF SR V1 (800W load) =
 = 71 % , Tmax = 75°C
Pnom = 150 kW cw
60 kW full reflection
Pr = kW
 minor modification on power combination
ESRF SR V2 (1.2kW load)
85 kW full reflection
Pr = kW
 modified combination
 kW load
ESRF SR V3 (power circul)
 Pnom = 140 kW
140 kW CW full reflection
+ 5% power loss
- 3% on efficiency
Extra costs
* VSWR limitation: when operating the amplifier at high CW incident power, Pi, with a high VSWR and the worst phase condition, an unpowered module (ie, both of its power supplies, or both sides of its push-pull broken) can see a power on its circulator load, Pload > Pi
Rem: full reflection for a short time (~10 ms) is not a problem ( Pr interlock)
♯ 2 PS in series on 2 modules in //
 VDMOS ; all the other cases are LDMOS

6. Gain of MOSFET
The Gain and Stability of a MOSFET depends on capacitance Crss between Gate and Drain LDMOS has much lower Crss than VDMOS The 6th Generation LDMOS has only about % of Crss than normal LDMOS due to the shield between the Gate and Drain

7. 6th Generation RF LDMOS (Laterally Diffused MOS)

8. Advantages of New Module with 6th Generation LDMOS
Anti-Thermal Fatigue (Special PCB Laminate, Super High Q Capacitors etc. Temperature < 80°C)
Higher Reliability, LDMOS MTBF > 2000 years (Transistor nominal power 1 kW)
Excellent Ruggedness
Higher Efficiency
Better Linearity
Lower tolerance of gain and phase
More Compact (Double density of RF Power)

9. BLF578 Module Characteristics
Module 500MHz
Module 352MHz

10. BLF578 Module Characteristics
Efficiency (%)
Gain (dB)
RF Power (W) (Output of Circutator)

11. Combination of Modules
How to combine 650 W modules to a 80 kW Tower
For a high power, coaxial system the traditional design: 90° 3 dB Hybrid.
For RF high power amplifier, Wilkinson Hybrid has bad performance due to the parasitic capacitance of floating power termination.
SOLEIL Design:
Each amplifier module is integrated with one circulator, the combiners become very simple.

12. 500 MHz 80 kW Tower

13. 8-Way 500 MHz 5 kW Power Combiner

14. 8-Way 500 MHz 40 kW Power Combiner

15. 2-Way 500 MHz 80 kW Power Combiner

16. 5 kW Double Directional Coupler

17. 2-Way 500 MHz Power Splitter

18. 8-Way 500 MHz Power Splitter

19. Upper Frequency Limits
For a coaxial line the frequency of operation is determined by the cut-off frequency fc of high order mode of propagation
The lowest fc occurs with the TE11 mode
Recommended Standard
50 Ohms 6-1/8’’ Coaxial Line Connector
TE11 Mode fc
880 MHz
Straight
830 MHz
Right Angle
580 MHz

20. CW Power Rating
At 500 MHz the CW power rating of 6-1/8’’ coaxial line is 77 kW
Based on VSWR = 1 with an ambient temperature 40°C and a maximum inner conductor temperature of 102°C.
At 500 MHz > 77 kW CW power the waveguide WR1800 should be used.
The traditional design:
2 pieces of waveguide to coaxial transition + waveguide Magic Tee or 90° 3 dB Hybrid + high power waveguide dummy load.
SOLEIL Design is much more simple

21. 500 MHz 150 kW Amplifier

22. 2-Way Loop Waco

23. 2-Way Antenna Waco

24. Conclusion of Waco Design
Emax (kV/m)
Hmax (A/m)
BW (MHz) S11 = -30 dB
Antenna Waco
299,4
334,5 45
Loop Waco
248,7
412,5 13
Advantages of Antenna Waco
1) Easy to be manufactured
2) Wider bandwidth
3) Low RF current density and Higher efficiency
4) Easy to be adjustable

25. 2-Way 500 MHz 150 kW Waco

26. 500 MHz Power Combiners

27. 4-Way 500 MHz 300 kW Waco

28. 4-Way 500 MHz Waco S11

29. 8-Way 500 MHz 600 kW Combiner

30. N-Way Waco Applications
N-Way Waco is not only able to be used for SSA of different frequency, but also for IOT and klystron amplifier as a power combiner
It is able to be used as power splitter also
Advantages
Low cost
Compact
Wide bandwidth

31. Thanks for your attention
Conclusion
SOLEIL Design Idea is able to be used for different frequency and different power SSA
It is low cost and compact design
Thanks for your attention